In recent years, in color display devices, methods for improving display luminance have been proposed. As an example, there has been proposed a liquid crystal display device in which one unit pixel is constituted by arranging a red (R) pixel, a green (G) pixel, a blue (B) pixel and a white (W) pixel in a row direction in a predetermined order.
The white pixel has a higher efficiency of use of light than the red pixel, green pixel and blue pixel, and the transmittance of the white pixel is about three times higher than the transmittance of each of the red pixel, green pixel and blue pixel. Thus, the area of the white pixel or the maximum value of the amount of transmissive light in the white pixel is not freely determined, but needs to be set in consideration of color reproducibility, etc. For example, the display luminance of the white pixel needs to be so set as to become a value lower than the total luminance of the red pixel, green pixel and blue pixel. Specifically, in a case where only the white pixel is enlarged, the display luminance is enhanced, but the color reproducibility deteriorates. In addition, the area of each of the red pixel, green pixel and blue pixel is sacrificed by an amount corresponding to the enlargement of the white pixel in the unit pixel of the limited area, and as a result the large white pixel cannot effectively be utilized.
Furthermore, in the case where the size of the white pixel has been enlarged, when an image with a high display luminance in the white pixel is displayed, the white pixel tends to be easily visually recognised, and consequently a displayed image tends to be visually recognized as a rough image.